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STRUCTURAL, OPTICAL, AND VISIBLE-LIGHT DRIVEN PHOTACATALYTIC PROPERTIES OF Yb-DOPED BiVO4 NANOPARTICLES PREPARED VIA RAPID SONOCHEMICAL PROCESS
(2023-01-01)
Boonyarattanakalin, Kanokthip
;
Noinonmueng, Tanisara
;
Kansaard, Thanaphon
;
Wechprasit, Tirapat
;
Mekprasart, Wanichaya
This work represents the synthesis and structural, morphological, and optical characterization of rare-earth Yb-doped BiVO<inf>4</inf> materials with different Ytterbium (Yb3+) contents (0% - 5%). Yb-doped BiVO<inf>4</inf> specimens in form of fine nanoparticles were synthesized by a rapid and facile sonochemical process. The structural and morphological characterizations were observed by X-ray diffraction technique (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Important optical properties of the prepared samples were investigated by the diffuse reflectance technique and the corresponding optical band gaps were calculated by the mean of the Kullbelka-Munk equation. From the characterized results, it is acknowledged that incorporated Yb dopant has a significant effect on the crystalline structure of BiVO<inf>4</inf> by reducing in monoclinic phase in the pristine sample while the increasing Yb doping composition resulted in the mixed phases of monoclinic and tetragonal phases since Yb3+ ions could probably induce the stabilization of the tetragonal phase in BiVO<inf>4</inf> material. Moreover, extensive doping with Yb3+ exhibits considerable influence on not only structural but also optical and relevant visible - driven photocatalytic properties of BiVO<inf>4</inf> by means of the color degradation of RhB dye solution
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Characterization, X-ray absorption spectroscopic analysis and photocatalytic activity of Co/Zn co-doped TiO2 nanoparticles synthesized by one-step sonochemical process
(2021-10-01)
Mekprasart, Wanichaya
;
Pavasupree, Sorapong
;
Jayasankar, C. K.
;
Ravuri, Balaji Rao
;
Wattanawikkam, Chakkaphan
A novel one-step preparation of sonochemical method was applied to synthesize Co/Zn co-doped TiO<inf>2</inf> nanoparticles using a sonicator of 750 W, 20 kHz for 30 min at room temperature. The formation of the anatase TiO<inf>2</inf> phase for all as-prepared samples was observed from XRD results with a crystalline size in nanoscale. The use of ultrasound allowed for the successful doping of both Co and Zn into the TiO<inf>2</inf> lattice, which was confirmed by Synchrotron light including X-ray near edge structure (XANES) and Extended X-ray absorption fine structure (EXAFS) spectroscopy. Ti K-edge, Co K-edge, and Zn K-edge XANES spectra exhibited the dominating +4, +2, and +2 valence state of Ti, Co, and Zn in as-prepared samples, respectively. A detailed XANES and EXAFS data analysis give strong evidence that the Co/Zn dopants partially replace the Ti atom of the TiO<inf>2</inf> host. The Co/Zn co-doping extends the light absorption of the host to the visible region and restricts the e+/h+ recombination. The photocatalytic activity of samples was tested for degradation of Rhodamine B dye solution under visible light irradiation. The as-synthesized of the co-doped catalyst was presented as highly efficient, with 2.5 and 5 times dye degradation compared with single-doped and bare TiO<inf>2</inf>.
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Effect of Ultrasonic Irradiation Time on Physical Properties and Photocatalytic Performance of BiVO4 Nanoparticles Prepared via Sonochemical Process
(2021-01-01)
Kansaard, Thanaphon
;
Bangbai, Chatpong
;
Jayasankar, C. K.
;
Pecharapa, Wisanu
Currently, photocatalyst materials have gained considerable attraction because of very rich economic performance of decomposition of highly toxic organic compound to lower toxic composition. The effort of this work was paid to study the effect of sonochemical ultrasonic irradiation time on the relevant properties of visible-light-driven bismuth vanadate (BiVO<inf>4</inf>) photocatalyst without any further thermal treatment process. The chemical bonding of BiVO<inf>4</inf> nanopowder was investigated by Fourier transform infrared (FTIR) and Raman spectrometer technique. Meanwhile their structure was characterized by X-ray diffraction technique (XRD). Field emission scanning electron microscope (FE-SEM) was used to observe particle morphology and chemical compositions was investigated by Energy-dispersive X-ray spectroscopy (EDX). Photocatalytic performance of BiVO<inf>4</inf> nanopowder was studied by decomposition of organic dye as organic pollutant model using visible light to excite photocatalyst materials. It was found that sonochemical irradiation time supplied during chemical process can effectively expedite the formation of BiVO<inf>4</inf> nanoparticle. The optimized condition to obtain the product with enhanced photocatalytic performance of 60% decomposition is achieved as the sample was prepared at 40 min ultrasonic irradiation.
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Structural studies and photocatalytic properties of Mn and Zn co-doping on TiO2 prepared by single step sonochemical method
(2020-06-01)
Wattanawikkam, Chakkaphan
;
Pecharapa, Wisanu
Titanium dioxide nanoparticles dual doped with zinc and manganese were prepared by the single step of sonochemical method using the sonicator with 20 kHz and 750 W for 30 min. Phase structure analysis results showed that the pure anatase phase was detected for all prepared samples. TEM analysis reveals the nanosized structure with uniformity of nanoparticles. The calculated bandgap energies change to be below the typical band gap energy of bare TiO<inf>2</inf> and single doped sample suggesting high ability to harvest visible light. X-ray absorption spectroscopy was conducted to investigate the electronics structure and to study the local structure of prepared samples. XANES results confirmed the existence of Ti4+ ions in all prepared samples with anatase crystal structure. EXAFS analysis indicates the Ti4+ site was substituted by Mn and Zn dopant ions. The photocatalytic performance was evaluated by degradation of Rhodamine B dye solution under visible light irradiation. The results revealed that the dually Mn–Zn doped TiO<inf>2</inf> sample exhibited excellent photocatalytic activity comparing to single doped and pure TiO<inf>2</inf>. The complete degradation of dye was achieved at optimum condition of 1 mol%-Zn and 2 mol%-Mn molar ratio. The highest photodegradation rate constant was found to be 0.0238 min−1, which is 10 times greater than pure-TiO<inf>2</inf> samples.
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Comparison study of photocatalytic activity of titanium-rich materials derived from natural minerals ores using acidic leaching
(2017-01-01)
Kansaard, Thanaphon
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Phoohinkong, Weerachon
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Mekprasart, Wanichaya
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Sanguanpak, Samanya
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Wannakon, Anucha
Over past decades, titanium dioxide-based materials have been recognized as effectively practical photocatalysts for purification of toxicity waste. However, pure TiO<inf>2</inf> photocatalyst is highly active under ultraviolet illumination. In this work, the effort has been focused on the synthesis of titanium-rich materials starting from minerals ores ilmenite ores and leucoxene ores by ball-milling process in combined with hydrochloric acid leaching method with optimized conditions. Crystallinity and morphologies of as-prepared samples were characterized by X-rays diffraction technique and scanning electron microscope. The photocatalytic activities of both derived-materials were studied and compared by degradation of Rhodamine B organic dye as organic toxicity compound under ultraviolet light and visible light. The results illustrate that the leucoxene-derived sample exhibits superior catalytic performance to the sample derived from ilmenite ores due to the greater Ti-content of the starting leucoxene ores.
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Photocatalytic activities under UV light of ball-milled TiO2photocatalysts
(2013-10-29)
Rattanarak, Jiravat
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Mekprasart, Wanichaya
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Pecharapa, Wisanu
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Techitdheera, Wicharn
Anatase TiO<inf>2</inf> powders used as photocatalysts were prepared by ball milling process at various milling time and annealed in nitrogen atmosphereat different temperatures. Commercial TiO<inf>2</inf> powders were ball-milled with ethanol at room temperature. After ball milling process, the samples were annealed in nitrogen atmosphere. The particle sizes and surface area of milled powders were measured by particle analyzer and Brunauer Emmet Teller method(BET). Effect of milling time and annealing temperature on structural properties of TiO<inf>2</inf> powders was investigated by X-ray diffraction(XRD) and scanning electron microscope(SEM). The degradation of aquous RhB dye by ball-milled TiO<inf>2</inf> powder photocatalyst was investigated under UV light irradiation. Comparing to P-25, TiO<inf>2</inf> powder prepared via ball milling process at 24 hr demonstrated significant enhancement in its photocatalytic activity under UV light due to the increasing active surface area after ball milling process. © (2013) Trans Tech Publications, Switzerland.
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Characterization and enhanced photocatalytic performance of nanocrystalline Ni-substituted Zn ferrites synthesized by DEA-assisted sol-gel auto-combustion method
(2013-06-01)
Tangcharoen, Thanit
;
Ruangphanit, Anucha
;
Klysubun, Wantana
;
Pecharapa, Wisanu
Nanocrystalline Ni-substituted Zn ferrites with compositions of Ni <inf>x</inf>Zn<inf>1-x</inf>Fe<inf>2</inf>O<inf>4</inf> (x = 0-1.0) were synthesized by sol-gel auto-combustion method using metal nitrate as the reactants. Diethanolamine was selected as the fuel instead of conventional fuels such as urea, citric acid, tartaric acid or glycine. Characterization of after-calcined ferrite samples were conducted in terms of crystal structure, molecular vibrations, morphology and magnetic properties through X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope and vibrating sample magnetometer analysis, respectively. The photocatalytic activities of these ferrites were studied in term of degradation of Rhodamine B under daylight-irradiation. The corresponding results indicate that nickel loading content has significant effect on physical, magnetic, optical and photocatalytic properties of the ferrite. Comparing to the undoped Zn ferrite, Ni<inf>0.6</inf>Zn<inf>0.4</inf>Fe<inf>2</inf>O<inf>4</inf> shows the enhancement in photocatalytic activity accompanying the degradation of Rhodamine B aqueous solution up to 77 % within 4 h. The result suggests the feasibility of this material as potential sunlight-activated photocatalyst in wastewater treatment and environment cleaning applications. © 2013 Springer Science+Business Media New York.
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Synthesis and characterization of nitrogen-doped TiO2 and its photocatalytic activity enhancement under visible light
(2011-01-01)
Mekprasart, Wanichaya
;
Pecharapa, Wisanu
Nitrogen-doped TiO<inf>2</inf> nanopowders were synthesized by homogenization and conventional mechanically stirred technique in DI water media. Different amount of nitrogen was loaded in TiO<inf>2</inf> matrix. As-obtained intermediate products were annealed at 100°C for 30, 60 and 120 min. The structural properties of samples were characterized by X-ray diffraction. The absorption spectrum of N-doped TiO<inf>2</inf> photocatalyst was analyzed via UV-Vis spectrophotometry. When doping TiO<inf>2</inf> with nitrogen, its absorption spectrum is shifted to visible region resulting in the enhancement of photocatalyst properties in dye photodegradation. The photocatalytic activity of TiO<inf>2</inf> and N-doped TiO<inf>2</inf> was investigated by the degradation of Rhodamine B dye under visible light. © 2011 Published by Elsevier Ltd.

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